Glossy and no reflection - only shadow
Looks like amount of light bounces for Glossy rays in your scene under the Light Paths rollout is set to 0 and looks like this:



This will make Cycles not to take into account rays which bounced from camera to the surface with only Glossy shader (e.g. plane supposed to be the floor also has glossy added to material nodes but it's mixed with Diffuse shader and Fresnel as the factor, so blackish reflection will be visible under certain angle).

Increase bounces to something more than 0, 8 by default and glossy reflections should appear.



Another possibility - Clamp Indirect under Sampling rollout is set to something really slow, like 0.0001. Then any reflections in the scene will be also black.



These values depend on the scene but generally you don't want them to be less than 1.